1. Field of the Invention.
The present invention relates to acoustic techniques for determining mapping data, such as topographic survey data, source and/or receiver position as well as wind or current and sound speed or temperature fields, from an environment. The present invention is particularly related to such techniques which utilize tomographic reconstruction to reduce ambiguities.
2. Description of the Prior Art.
The use of acoustic techniques to localize natural sounds when the transmission times are not known is discussed by Watkins and Schevill in "Four hydrophone array for acoustic three-dimensional location", Woods Hole Oceanographic Institution Technical Report 71-60, 1971.
The use of tomographic techniques to localize artificial transmitters with known transmission times and nearly known positions is discussed by B. D. Cornuelle in "Simulations of acoustic tomography array performance with untracked or drifting sources and receivers", J. Geo. Res. 90 (C5), pp. 9079-9088, 1985.
Such conventional techniques do not provide method or apparatus for accurately mapping acoustic source positions, improving estimates of receiver positions and mapping wind current and sound speed fields when the transmission times